Re: [syslog-ng] How to log messages generated by C program and log file rotation

6 Aug 2014

      Your C program is using the syslog API to the kernel. This will only ever be available via
the /dev/log mechanism exposed by the kernel.

Your current syslog-ng.conf file specifies a source of

     source s_mysource {
          pipe("/tmp/pipe" pad_size(2048));
     };

which is not where the C call of syslog() sends the syslog messages.

Like Balazs stated, you need to use the syslog-ng system() source or define a syslog-ng source containing unix-dgram("/dev/log")
in order to read out the messages produced by the call to syslog() from your C program.

Evan.

On 08/06/2014 07:49 AM, Balazs Scheidler wrote:
...
Hi,
You seem to have defined the source as a named pipe whereas the libc usually uses a UNIX domain socket to send messages.
Why don't you simply use the system() source? Or at least define use unix-dgram("/dev/log")
On Aug 6, 2014 11:11 AM, "Jean Faye" <ismael.faye@yahoo.fr <mailto:ismael.faye@yahoo.fr>> wrote:
Hi all,
    I want to use syslog-ng to log the messages generated by my application implemented in C language. I added this in the code:
char    *log="rtcd";
         printf("[%s] RTC adjustement\n",__func__);
         openlog(log, LOG_PID, LOG_LOCAL0);
         syslog(LOG_DEBUG, "[FIJ] RTC adjustement");
         closelog();
For me, according to the syslog-ng file, the files /var/log/ldb/GENTrace.log, /var/log/ldb/SUTrace.log, /var/log/ldb/WANTrace.log and /var/log/ldb/CPLTrace.log must be created and must contain the syslog message.
    But I got no messages in my destination files. You can see the content of my syslog-ng.conf file bellow.
Is it the right way to log the messages sent by C program? What can explain that I got no messages in the destinations files?
I am using syslog-ng 3.5.4.1 provided by yocto. And in the script which run the binary (initscript file) I remove the line below:
. /etc/init.d/functions
Why are you using the line? Is it necessary to use it?
Concerning log file rotation, How can we manage it using syslog-ng? For example I want to have a destination file with a size maximum = 2Mo and if the size is greater than the max size, I have to save the current one and create a new one. On my system I can have max 4 files (4 x 2Mo). How can I manage this kind of rotation?
Thanks in advance.
    Best regards,
    Ismael Jean FAYE
@version: 3.5
    #
    # Syslog-ng configuration file, compatible with default Debian syslogd
    # installation. Originally written by anonymous (I can't find his name)
    # Revised, and rewrited by me (SZALAY Attila <sasa@debian.org <mailto:sasa@debian.org>>)
# First, set some global options.
    options { chain_hostnames(off); flush_lines(0); use_dns(no); use_fqdn(no);
           owner("root"); group("adm"); perm(0640); stats_freq(0);
           bad_hostname("^gconfd$");create_dirs(yes);
    };
########################
    # Sources
    ########################
source s_mysource {
         pipe("/tmp/pipe" pad_size(2048));
    };
########################
    # Destinations
    ########################
destination d_GEN {
                     file("/var/log/ldb/GENTrace.log");
    };
destination d_SU {
                     file("/var/log/ldb/SUTrace.log");
    };
destination d_WAN {
                     file("/var/log/ldb/WANTrace.log");
    };
destination d_CPL {
                     file("/var/log/ldb/CPLTrace.log");
    };
########################
    # Filters
    ########################
filter f_GEN {
                     #facility(local0) and filter(nom_du_composant_applicatif);
                     #facility(local0) and filter(f_debug);
              facility(local0);
    };
filter f_SU {
                     #facility(local0) and filter(nom_du_composant_applicatif);
                     #facility(local0) and filter(f_debug);
                     facility(local0);
    };
filter f_WAN {
                     #facility(local0) and filter(nom_du_composant_applicatif);
                     #facility(local0) and filter(f_debug);
                     facility(local0);
    };
filter f_CPL {
                     #facility(local0) and filter(nom_du_composant_applicatif);
                     #facility(local0) and filter(f_debug);
                     facility(local0);
    };
########################
    # Log paths
    ########################
log { source(s_mysource); filter(f_GEN); destination(d_GEN); };
    log { source(s_mysource); filter(f_SU); destination(d_SU); };
    log { source(s_mysource); filter(f_WAN); destination(d_WAN); };
    log { source(s_mysource); filter(f_CPL); destination(d_CPL); };
Le Mardi 5 aoÃ»t 2014 16h05, Jean Faye <ismael.faye@yahoo.fr <mailto:ismael.faye@yahoo.fr>> a Ã©crit :
confirm a6d843f7ad7d1dbf1fefb6f12432e54941a680a9
Hi all,
    I want to use syslog-ng to log the messages generated by my application implemented in C language. I added this in the code:
char    *log="rtcd";
         printf("[%s] RTC adjustement\n",__func__);
         openlog(log, LOG_PID, LOG_LOCAL0);
         syslog(LOG_DEBUG, "[FIJ] RTC adjustement");
         closelog();
For me, according to the syslog-ng file, the files /var/log/ldb/GENTrace.log, /var/log/ldb/SUTrace.log, /var/log/ldb/WANTrace.log and /var/log/ldb/CPLTrace.log must be created and must contain the syslog message.
    But I got no messages in my destination files. You can see the content of my syslog-ng.conf file bellow.
Is it the right way to log the messages sent by C program? What can explain that I got no messages in the destinations files?
Concerning log file rotation, How can we manage it using syslog-ng? For example I want to have a destination file with a size maximum = 2Mo and if the size is greater than the max size, I have to save the current one and create a new one. On my system I can have max 4 files (4 x 2Mo). How can I manage this kind of rotation?
Thanks in advance.
    Best regards,
    Ismael Jean FAYE
@version: 3.5
    #
    # Syslog-ng configuration file, compatible with default Debian syslogd
    # installation. Originally written by anonymous (I can't find his name)
    # Revised, and rewrited by me (SZALAY Attila <sasa@debian.org <mailto:sasa@debian.org>>)
# First, set some global options.
    options { chain_hostnames(off); flush_lines(0); use_dns(no); use_fqdn(no);
           owner("root"); group("adm"); perm(0640); stats_freq(0);
           bad_hostname("^gconfd$");create_dirs(yes);
    };
########################
    # Sources
    ########################
source s_mysource {
         pipe("/tmp/pipe" pad_size(2048));
    };
########################
    # Destinations
    ########################
destination d_GEN {
                     file("/var/log/ldb/GENTrace.log");
    };
destination d_SU {
                     file("/var/log/ldb/SUTrace.log");
    };
destination d_WAN {
                     file("/var/log/ldb/WANTrace.log");
    };
destination d_CPL {
                     file("/var/log/ldb/CPLTrace.log");
    };
########################
    # Filters
    ########################
#filter f_GEN {
                     #facility(local0) and filter(nom_du_composant_applicatif);
                     #facility(local0) and filter(f_debug);
                     #facility(local0);
    #};
filter f_SU {
          #facility(local0) and filter(nom_du_composant_applicatif);
                     #facility(local0) and filter(f_debug);
                     facility(local0);
    };
filter f_WAN {
                     #facility(local0) and filter(nom_du_composant_applicatif);
                     #facility(local0) and filter(f_debug);
                     facility(local0);
    };
filter f_CPL {
                     #facility(local0) and filter(nom_du_composant_applicatif);
                     #facility(local0) and filter(f_debug);
                     facility(local0);
    };
########################
    # Log paths
    ########################
#log { source(s_mysource); filter(f_GEN); destination(d_GEN); };
    log { source(s_mysource); filter(f_SU); destination(d_SU); };
    log { source(s_mysource); filter(f_WAN); destination(d_WAN); };
    log { source(s_mysource); filter(f_CPL); destination(d_CPL); };
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______________________________________________________________________________
Member info: https://lists.balabit.hu/mailman/listinfo/syslog-ng
Documentation: http://www.balabit.com/support/documentation/?product=syslog-ng
FAQ: http://www.balabit.com/wiki/syslog-ng-faq
-- 
Evan Rempel                                      erempel@uvic.ca
Senior Systems Administrator                        250.721.7691
Data Centre Services, University Systems, University of Victoria